( only four years after the original post! )

I haven't tested this with the WaveOut portion of the Win32::Sound module, but the logic seems nearly identical in both the Win32::Sound and Win32::Sound::Waveout sections of Sound.c. Basically, snag the module, edit Sound.c and change all occurrences of '<< 8' to '<< 16' and only use 0-65536 for volume changes, not the percentage notation as specified by the documentation. This fix is only a few minutes old but I've been able to successfully set the left and right channels independently or synched, so for now that's good enough.

( note : I was using this under Cygwin but I expect it should work equally well with Activestate )